Flexible polyimide chemical sensors using platinum nanoparticles

Platinum nanoparticles without any prior chemical modification and poly(2-hydroxyethyl methacrylate) (PHEMA) have been employed as the transducing and gas sensitive layer respectively for this flexible chemical sensing application. Using a modified magnetron sputtering technique, gas phase platinum nanoparticles have been deposited on top of flexible polyimide substrates. The surface density of such nanoparticle films can be controlled via the overall deposition time, producing devices of varying conductivity. A layer of PHEMA polymer (500–700 nm thick) has been ink-jet printed on top of the nanoparticle film finalizing the sensor's fabrication. By exposing the sensor in ethanol or humidity vapors a change in the film's resistance or capacitance is observed facilitating the detection of such gases. The performance of these sensors has been connected with the nanoparticle film resistance.